UMEM Educational Pearls - By Duyen Tran

Category: Critical Care

Title: Myocarditis

Posted: 11/23/2021 by Duyen Tran, MD (Updated: 12/7/2021)
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Myocarditis is a potentially fatal inflammatory disorder of the heart. Viral infection is the most common cause but can also result from toxic, autoimmune, or other infectious etiologies. Complications include life-threatening dysrhythmias, heart failure, and fulminant myocarditis. Typically affects young patients (20-50 years old).

  • Diagnosis can be challenging. Presentation can range from nonspecific symptoms and normal hemodynamics to cardiogenic shock.
  • Dyspnea was found to be the most common presenting symptom in one study
  • Other symptoms include fever, malaise, chest pain, palpitations, fatigue, nausea, vomiting
  • Consider the diagnosis in young patient with suspected sepsis but worsens with IV fluids with signs of volume overload
  • Initial assessment should include ECG, CBC, CMP, inflammatory markers, cardiac biomarkers, CXR. Obtaining an echo is important. Perform POCUS to assess for global hypokinesis, reduced EF, wall motion abnormalities, pericardial effusion, B-lines.

ED management pearls

  • Initiate vasopressors and inotropic support if hemodynamically unstable: norepinephrine + inotropic agent (e.g. milrinone, dobutamine) is recommended. In a few studies, epinephrine was associated with increased mortality when used in cardiogenic shock.
  • Diurese if evidence of volume overload
  • NIPPV or intubation if respiratory failure
  • Avoid NSAIDs which may worsen mortality
  • Consider mechanical circulatory support (e.g. ECMO, IABP, VAD) in refractory hypotension despite appropriate medical therapy

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Intubation considerations

  • Use large ET tube (at least 8.0 if possible): minimizes airway resistance, facilitates aggressive pulmonary toilet and bronchoscopy if needed
  • Consider using ketamine as induction agent as it has bronchodilator properties and can maintain blood pressure
  • Appropriate choices for initial sedation includes propofol, fentanyl, and ketamine

Vent management strategies

  • No overall outcome differences between volume vs pressure control modes. Volume control has been recommended as initial mode due to familiarity and ensures your set tidal volume will be delivered.
  • Goal is to minimize autoPEEP, which occurs from incomplete exhalation prior to initiation of next inhaled breath. This can be achieved by adjusting a few vent settings: decreasing RR, decreasing I:E ratio, decreasing inspiratory time, or increasing inspiratory flow rate. Allow for permissive hypercapnia, pH >7.2 has been advocated though precise target is unknown.
  • If patient becomes hemodynamically unstable, consider first disconnecting the ventilator from the ET tube and manually decompress the chest to facilitate exhalation.
  • Peak inspiratory pressures are expected to be high in the acute severe asthmatic. More important is to keep plateau pressures <30 cm H2O to prevent lung injury.
  • Don't forget to continue asthma-directed therapy. Administer albuterol via in-line nebulization unit of the vent.

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